1. Field of the Invention
The present invention relates to the field of aircraft safety, and more particularly to the detection and location of clear air wind shear conditions, clear air turbulence, cross wind velocity, and aircraft generated vortices.
2. Description of the Prior Art
Aircraft generated vortices, clear air turbulence, cross winds, and (horizontal) wind shear all present severe hazards to aircraft which inadvertently encounter any of these conditions in the approach (or departure) glide slope corridors. Aircraft can be subjected to movements which result in a dangerous loss of altitude, and possibly structural failure. Such encounters are most dangerous in the terminal area glide slopes where recovery from an upset may not be possible due to the aircraft altitude.
Although the phenomenon of aircraft wake vortices has been known since the beginnings of powered flight, it is only since 1970 that the danger of aircraft encounters with wake vortices has become apparent. All aircraft generate vortices as a result of generating lift, including helicopters. Landing aircraft separations are dictated by the time for vortices to decay. Heavier aircraft generate stronger vortices than light aircraft and require larger separations behind them. Thus aircraft vortices impact both airport capacity and safety.
Since a cross wind can blow vortices out of the glide slope, knowledge of cross wind velocity by direct measurement in each range bin along the glide slope can result in reduced spacings between landing aircraft, thereby increasing the number of landings per hour at busy airports. Previous systems which have extrapolated cross wind velocity from measurements elsewhere have proved to be unreliable and hazardous to landing aircraft.